It is conventional to use an auger when drilling into the earth whether the hole to be produced is shallow as for a post hole, or deep, as for a well or for seismic exploration. For such conventional drilling the flight of the auger has its helix oriented in the same direction as the rotation of the auger. Thus a drill or auger which rotates in the clockwise direction has a right-hand or clockwise flight. With this type of conventional auger the flight tends to pull the auger down into the earth and the material (tailings) removed from the hole is forced up the auger to the surface by the flight. If the auger becomes clogged by the material it is necessary to lift the auger from the hole for cleaning. As the hole becomes deeper and/or dense material such as clay is encountered it becomes progressively more difficult to remove the auger for cleaning. Also the hole wall tends to continuously collapse, making removal of the auger more difficult, making drilling more difficult or possibly resulting in a broken auger.
When drilling bore holes for seismic exploration or when drilling deeper, as for a well, it is conventional to use a drill string made up of a plurality of lengthsdrilling mud passes downwardly through the drill string to the drill bit secured to the downhole end of the lowermost drill steel so as to lubricate and cool the drill bit and to help carry the tailings upwardly to the surface. The same problems resulting from clogging of the auger, as discussed above, apply to drill strings as well.
When drilling for seismic exploration or for wells there is an even greater problem, represented by the talings and mud brought to the surface by the auger. The tailings and mud are distributed about the hole on the surface and are considered to be unacceptable by many enviromental protection agencies or groups. The tailings and mud, especially if chemically treated as is often the case, can damage lakes and streams. Chemically treated mud can also leak into underground streams unknown to the operators, and if the streams discharge into lakes or rivers it is often impossible to determine the sorurce of the pollution. A large sub-industry has developed recently solely for the purpose of cleaning up drilling sites and this of course increases greatly the cost of a drilling operation.